What is the difference between == and === in JavaScript?

== performs type-coercing equality comparison while === performs strict equality without type coercion. Prefer === for predictable comparisons.

JavaScript Operators — Arithmetic, Comparison, Logical & Assignment

Operators
Arithmetic
Logical
Assignment
Comparison

Operators

JavaScript operators are used to perform tasks like assignment, addition, subtraction, and comparisons. JavaScript provides arithmetic, logical, assignment, and comparison operators.

JavaScript also supports binary and unary operators, as well as the ternary (conditional) operator.

Binary operator

Binary operators require two operands, one before and one after the operator. x + y = z

x (operand) +(operator)  y(operand)

Unary Operator

Unary operators require only one operand, either before or after the operator. i++

x++

++x

Ternary Operator

Ternary Operator is the conditional operator in JavaScript which uses three operands. For example, (3>2) ? console.log("yes") : console.log("no") will print yes, while (1>2) ? console.log("yes") : console.log("no") will print no.

yes

(3>2) ? console.log("yes") : console.log("no");

(1>2) ? console.log("yes") : console.log("no");

Arithmetic Operators

An Arithmetic operator is used to perform Arithmetic operations between values. Like Addition, Subtraction, Multiplication, Division etc

Arithmetic operators in JavaScript

Operator	Description	Example
+	Addition, can also concat	2+3=5 "2" + 3 = "23"
-	Subtraction	5-3=2 "5" - 3 = 2
*	Multiply	2*3=6
/	Divide	6/3=2
%	Remainder	6%3=0
++	Increment, y++ means y = y+1	var y=2; ++y; y=3
--	Decrement, y-- means y = y-1	var y=2; --y; y=1
**	Exponentiation Operator	2**3 returns 8

The ** Exponentiation Operator was introduced in JS ES7. There is no support for Exponentiation Operator in IE browser, chrome<52 and Firefox<52

Logical Operators

Logical Operators are used to check logic between two operators. and (&&), or (||) and not (!) are logical operators.

Logical Operators in JavaScript

Operator	Description	Example
&&	and, when both are correct	2 < 5 && 2> 1 is true
\|\|	or, when any one is correct	var x=2, 2>5 \|\| x==2 is true
!	not	!(2==3) is true

Assignment Operators

Assignment operators are used to assign values to JavaScript variables. Examples include =, +=, -=, *=, and /=.

Assignment Operators in JavaScript

Operator	Description	Example
=	Assignment	x=2; means x is 2
+=	Addition Assignment	let x=2; x+=2 means x=x+2
-=	Subtraction Assignment	let x=2; x-=2 means x=x-2
*=	Multiplication Assignment	let x=2; x=2 means x=x2
/=	Division Assignment	let x=2; x/=2 means x=x/2
??	Nullish coalescing	null ?? 0 return 0 undefined ?? 0 return 0

The ?? Nullish coalescing was introduced in JS ES 2021.

Comparison Operators

Comparison operators are used in a statement to compare two values. Like == is used to compare values but === is used to compare values and datatypes.

Comparison Operators in JavaScript

Operator	Description	Example
==	Equal to, check value only	2 == "2" is true true == 1 is true undefined == null is true
===	Strict equal to, check value and data type both	2==="2" is false true === 1 is false undefined === null is false
!=	not equal	2!=1 is true
!==	not strict equal	2!=="2" is true
>	greater than	2> 5 is false, & 2 <5 is true
>=	greater than or equal to	3>=3 is true
<	less than	1< 3 is true
<=	less than or equal to	2<=2 is true

Key takeaways

Prefer === (strict equality) to avoid unexpected type coercion from ==.
Use parentheses to make complex expressions clearer and avoid operator precedence bugs.
Check browser compatibility for newer operators like ** and ??.

JavaScript Operators